Queries to find the maximum and minimum array elements excluding elements from a given range

// C# program for the above approach
using System;
public class GFG
{

  // Function to find the maximum and
  // minimum array elements up to the i-th index
  static void prefixArr(int[] arr, int[,] prefix, int N)
  {

    // Traverse the array
    for (int i = 0; i < N; i++)
    {
      if (i == 0)
      {
        prefix[i, 0] = arr[i];
        prefix[i, 1] = arr[i];
      }
      else
      {

        // Compare current value with maximum
        // and minimum values up to previous index
        prefix[i, 0] = Math.Max(prefix[i - 1, 0], arr[i]);
        prefix[i, 1] = Math.Min(prefix[i - 1, 1], arr[i]);
      }
    }
  }

  // Function to find the maximum and
  // minimum array elements from i-th index
  static void suffixArr(int[] arr, int[,] suffix, int N)
  {

    // Traverse the array in reverse
    for (int i = N - 1; i >= 0; i--) 
    {
      if (i == N - 1)
      {
        suffix[i, 0] = arr[i];
        suffix[i, 1] = arr[i];
      }
      else
      {

        // Compare current value with maximum
        // and minimum values in the next index
        suffix[i, 0] = Math.Max(suffix[i + 1, 0], arr[i]);
        suffix[i, 1] = Math.Min(suffix[i + 1, 1], arr[i]);
      }
    }
  }

  // Function to find the maximum and
  // minimum array elements for each query
  static void maxAndmin(int[,] prefix,
                        int[,] suffix,
                        int N, int L, int R)
  {
    int maximum, minimum;

    // If no index remains after
    // excluding the elements
    // in a given range
    if (L == 0 && R == N - 1)
    {
      Console.WriteLine("No maximum and minimum value");
      return;
    }

    // Find maximum and minimum from
    // from the range [R + 1, N - 1]
    else if (L == 0) 
    {
      maximum = suffix[R + 1, 0];
      minimum = suffix[R + 1, 1];
    }

    // Find maximum and minimum from
    // from the range [0, N - 1]
    else if (R == N - 1)
    {
      maximum = prefix[L - 1, 0];
      minimum = prefix[R - 1, 1];
    }

    // Find maximum and minimum values from the
    // ranges [0, L - 1] and [R + 1, N - 1]
    else 
    {
      maximum = Math.Max(prefix[L - 1, 0],
                         suffix[R + 1, 0]);
      minimum = Math.Min(prefix[L - 1, 1],
                         suffix[R + 1, 1]);
    }

    // Print the maximum and minimum value
    Console.WriteLine(maximum + " " + minimum);
  }

  // Function to perform queries to find the
  // minimum and maximum array elements excluding
  // elements from a given range
  static void MinMaxQueries(int[] a, int[,] Q)
  {

    // Size of the array
    int N = a.GetLength(0);

    // Size of query array
    int q = Q.GetLength(0);

    // prefix[i][0]: Stores the maximum
    // prefix[i][1]: Stores the minimum value
    int[,] prefix = new int[N, 2];

    // suffix[i][0]: Stores the maximum
    // suffix[i][1]: Stores the minimum value
    int[,] suffix = new int[N, 2];

    // Function calls to store
    // maximum and minimum values
    // for respective ranges
    prefixArr(a, prefix, N);
    suffixArr(a, suffix, N);

    for (int i = 0; i < q; i++)
    {
      int L = Q[i, 0];
      int R = Q[i, 1];
      maxAndmin(prefix, suffix, N, L, R);
    }
  }

  // Driver Code
  static public void Main ()
  {
    
    // Given array
    int[] arr = { 2, 3, 1, 8, 3, 5, 7, 4 };
    int[,] queries = { { 4, 6 }, { 0, 4 }, 
                      { 3, 7 }, { 2, 5 } };
    MinMaxQueries(arr, queries);
  }
}

// This code is contributed by sanjoy_62.